1. Field
The following description relates to a power device and to, for example, a lateral double-diffused metal oxide semiconductor (LDMOS) with an expanded drain region that exhibits a high breakdown voltage and a fast switching response.
2. Description of Related Art
MOSFET devices have been widely used in power conversion and regulation circuits due to their high-switching frequency and low power loss. There are various types of power MOSFET devices known as double-diffused MOS transistors. For example, a vertical version of double-diffused MOS transistor is known as a vertical double-diffused metal oxide semiconductor (VDMOS). A lateral version of double-diffused MOS transistor is known as a lateral double-diffused metal oxide semiconductor (LDMOS).
When a silicon-on-insulator (SOI) substrate is used to fabricate a power integrated circuit (IC), the fabrication process may be simplified in comparison to using a bulk silicon substrate. However, the SOI substrate is too expensive for most applications. Further, VDMOS transistors have large power handling capabilities; however, VDMOS transistors are more difficult to implement in an IC technology in comparison to LDMOS transistors.
LDMOS devices are widely used as a switch for control, logic, and power. LDMOS devices have to exhibit a high breakdown voltage (BV) to endure a high applied voltage as well as low specific on-resistance Rsp to minimize conduction losses. Rsp is defined as the resistance of the device times its active area.
However, current LDMOS devices have a structure incapable of providing the high breakdown voltage and low specific on-resistance, and this limits improvements that may be made to the switching characteristics of the LDMOS devices.